Such release ski bindings are described in German Pat. No. 25 33 337. In these conventional ski bindings, the spring of the holding mechanism acts through a piston onto a generally mushroom-shaped follower member swingably supported for movement to all sides in the housing of the holding mechanism. The stem part of the mushroom-shaped follower member is received in a recess in a ski-fixed fitting. In these conventional ski bindings, the ski shoe is held at its tip by means of a rigid bar on the sole plate. In the case of a fall of the skier rearwardly, the ski shoe is therefore released only with great difficulty.
The aforementioned disadvantage is avoided in the ski binding disclosed in German Pat. No. 23 24 078, however, this binding is very complicated in its design. Further, the release mechanism is housed in the space between the base plate and the sole plate. However, this requires special sealing measures to protect against the penetration of snow and dirt. Furthermore the mounting is complicated and expensive.
The goal of the invention is to overcome the listed disadvantages of the conventional designs and to provide a release ski binding of the above-mentioned type, which is simple in its design and is inexpensive to manufacture and which opens also during rearward falls of the skier.
This goal is inventively achieved primarily by the holding mechanism having associated with it a spring housing which is movably supported on the sole plate, the spring of which housing urges a locking member for the jaws which hold the ski shoe into the clamping position. The locking member is arranged on the sole plate. If in this ski binding, the elastic range of the sole plate is exceeded, the spring housing is released by the holding mechanism, and the locking member is pulled back to open the jaws to release the ski shoe. Thus in every case, regardless of which direction the fall of the skier occurs, a release of the ski shoe is caused.
It has been proven to be particularly preferable if, in a further development of the invention, a two-arm lever is pivotally supported on a transverse axis in the holding mechanism and is secured in an end position, one arm of which is supported with its front side on a roller rotatably supported on the spring housing, for example on an extension of the same. In this manner, the precision of the reaction of the holding mechanism to outside influences by the skier are considerably improved, since the friction occurring during a movement of one arm of the two-arm lever relative to the roller is extremely low.
In order to prevent in a particularly simple manner the arm of the two-arm lever from sliding off from engagement with the roller, for example, under the influence of vibrations during the skiing, the invention further provides that the two-arm lever in the skiing position engages, under the influence of a torsion spring, a stop provided on the holding mechanism. It has been proven to be preferable that one arm of the lever be constructed fork-shaped.
As it is known, the holding force acting in a vertical longitudinally extending center plane of the ski and which is to be overcome during a frontal fall, is to be approximately three times as great as the force in the horizontal plane, which must be overcome during a twisting fall. In order to meet these different torsional moments, various inventive solutions are offered. Thus it is possible in a ski binding, in which the spring of the holding mechanism acts through a piston onto a generally mushroom-shaped follower member, to support the housing of the holding mechanism so that it is swingable to all sides, for the stem of the follower member to inventively have at an axial spacing therebetween two spherical ball-shaped portions, one of which is guided in a horizontally extending guide and the other in a vertically extending groove or guide of a ski-fixed fitting, and for the two-arm lever to rest on a transversely extending bolt of a piston.
A different embodiment of a ski binding, in which the spring of the holding mechanism acts through at least one piston onto a generally mushroom-shaped follower member swingably supported for movement to all sides in the housing of the holding mechanism, is inventively characterized (1) by the stem of the follower member having a spherical end guided in a bore of a ski-fixed fitting, and (2) by two pistons which are guided in or on one another and which engage the backside of the follower member, one piston of which is loaded by a first pressure spring for a release in the horizontal plane and the other piston by a second pressure spring for a release in the vertical plane.
Springs which are separate for both torsional moments are hereby utilized to facilitate an easier adjustment to the capabilities and the constitution of the skier. In order to be able to carry out an adjustment of the initial tension of the two springs, the invention provides that the two springs are housed in a rocker arm which is pivotally supported for movement about a transversely extending axis in the holding mechanism. The angular position of the rocker arm can be changed by an adjusting screw. Levers are swingably supported between the springs and the pistons in the holding mechanism. These levers engage the backside of the coaxially arranged pistons. These intermediate levers assure a satisfactory transfer of the spring force at different angular positions of the spring housing.
Furthermore the invention provides that the inner piston carries on its front side a horizontal control bar, whereas the outer piston has two control projections. The centers or axes of the pistons lie in a common vertical plane. Further, the ends of the control projections and of the control bar lie, in the normal position of the holding mechanism, in a plane which is perpendicular to the axis of the hole. These characteristics assure--regardless whether a frontal fall, a twisting fall or a combination fall occurs--a satisfactory transfer of the release force from the follower member to the two-arm lever. Furthermore in this embodiment, one arm of the two-arm lever is bifurcated and each leg engages simultaneously two shoulders on the two pistons. Through this the two-arm lever is swung always when one or the other or both pistons are moved against the force of the springs.